<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div {
            width: 300px;
            height: 200px;
            /*border-width: 5px ;*/
            /*border-style: dotted;*/
            /*border-color: cadetblue;*/
            border: 5px dotted cadetblue;
            border-top: 6px solid gray;
            text-align: center;
            line-height:200px
        }
    </style>
</head>
<body>
<div>
    盒子
</div>
</body>
</html>